Silence.EDA Detection — Sigma Rule

Rule metadata and linked tags

Author: Alina Stepchenkova, Group-IB, oscd.community. Source status: test; severity: critical. Source dates: 2019-11-01 / 2023-04-03.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 73a67d10262bc8d19ddf40fcd858981b27ce262f97ef29db88d4eb5628327f58

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Silence.EDA Detection
id: 3ceb2083-a27f-449a-be33-14ec1b7cc973
status: test
description: Detects Silence EmpireDNSAgent as described in the Group-IP report
references:
    - https://www.group-ib.com/resources/threat-research/silence_2.0.going_global.pdf
author: Alina Stepchenkova, Group-IB, oscd.community
date: 2019-11-01
modified: 2023-04-03
tags:
    - attack.execution
    - attack.t1059.001
    - attack.command-and-control
    - attack.t1071.004
    - attack.t1572
    - attack.impact
    - attack.t1529
    - attack.g0091
    - attack.s0363
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    empire:
        # better to randomise the order
        ScriptBlockText|contains|all:
            - 'System.Diagnostics.Process'
            - 'Stop-Computer'
            - 'Restart-Computer'
            - 'Exception in execution'
            - '$cmdargs'
            - 'Close-Dnscat2Tunnel'
    dnscat:
        # better to randomise the order
        ScriptBlockText|contains|all:
            - 'set type=$LookupType`nserver'
            - '$Command | nslookup 2>&1 | Out-String'
            - 'New-RandomDNSField'
            - '[Convert]::ToString($SYNOptions, 16)'
            - '$Session.Dead = $True'
            - '$Session["Driver"] -eq'
    condition: empire and dnscat
falsepositives:
    - Unknown
level: critical

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.group-ib.com/resources/threat-research/silence_2.0.going_global.pdf